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More About Syncope

Vasovagal syncope is a condition that leads to fainting in some people. It is the most common cause of fainting. It's usually not harmful nor a sign of a more serious problem.

Many nerves connect with your heart and blood vessels. These nerves help control the speed and force of your heartbeat. They also regulate blood pressure by controlling whether your blood vessels widen or tighten. Usually, these nerves coordinate their actions so you always get enough blood to your brain. Under certain situations, these nerves might give an inappropriate signal. This might cause your blood vessels to open wide. At the same time, your heartbeat slows down. Blood can start to pool in your legs, and not enough of it may reach the brain. If that happens, you may briefly lose consciousness. When you lie or fall down, blood flow to the brain resumes.

Vasovagal syncope is quite common. It most often affects children and young adults, but it can happen at any age. It happens to men and women in about equal numbers. Unlike some other causes of fainting, vasovagal syncope does not signal an underlying problem with the heart or brain.

Several triggers can cause vasovagal syncope. To help reduce the risk of fainting, you can avoid some of these triggers such as:

  • Standing for long periods
  • Excess heat
  • Intense emotion, such as fear
  • Intense pain
  • The sight of blood or a needle
  • Prolonged exertion
  • Dehydration
  • Skipping meals

Older adults may have other specific triggers, for example:

  • Urinating
  • Swallowing
  • Coughing
  • Having a bowel movement

See a doctor right away if you have recurrent episodes of passing out or other related problems.